Dispense nozzle with a shielding device

ABSTRACT

Provided is a nozzle system for dispensing a dispense chemical onto a substrate, the system comprising: a nozzle comprising a nozzle body and a nozzle tip; a shielding device coupled to the nozzle tip, the shielding device configured to create a mini-environment for a dispense chemical such that a partial pressure of the dispense chemical is maintained in the shielding device; wherein the nozzle system is configured to meet selected dispense objectives.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to a system and method for keeping the substrateclean and free of particles and specifically to a system and method ofensuring that dispense nozzles are clean and free of particles and donot allow the dispense chemical to drift into the substrate after thedispensing of the chemical.

Description of Related Art

Dispense nozzles for resist, solvent and other semiconductor chemicalsmust be kept clean and free of particles in order to eliminate defectson processed substrates. Additionally, a nozzle must not drip at thecompletion of the dispense, which can also lead to substrate defects. Inmost advanced track tools, suck back valves have been incorporated toeliminate the possibility of drips as well as reduce evaporation at thetip of the nozzle. As the chemicals in the resist evaporate, they canleave behind dried particles which can easily be transferred to thesubstrate. If the chemical is left exposed at the tip of the nozzle, theevaporated gas is quickly blown from the surface as the nozzle is movedfrom position to position, thereby maintaining a low partial pressureand a high evaporation rate. By sucking the chemical back into the tube,a micro-environment is created in the vacated part of the tube where ahigh partial pressure can be maintained and which is only reduced viadiffusion, a much slower process thereby reducing the particlegeneration rate due to evaporation.

The drawback to such an approach is the complexity of the required suckback hardware, which is typically incorporated into the dispense valve.It would be advantageous in terms of cost, weight, and system complexityto eliminate the suck back feature, which is one the objects of thisinvention.

Proper nozzle tip and valve design combined with precision operationenables the flow to be shut off without the risk of additional drops. Inthis state, the dispense chemical is held at the tip of the nozzle bythe surface tension of the dispense chemical. There is a need for ashielding device and method where a mini-environment is created aroundthe nozzle tip similar to the environment created in the nozzle tipduring suck back. The shielding device needs to prevent external airmovements from rapidly purging away the evaporated gas, therebyproviding the same protection without the added complexity of a suckback process.

SUMMARY OF THE INVENTION

Provided is a nozzle system for dispensing a dispense chemical onto asubstrate, the system comprising: a nozzle comprising a nozzle body anda nozzle tip; a shielding device coupled to the nozzle tip, theshielding device configured to create a mini-environment for a dispensechemical such that a partial pressure of the dispense chemical ismaintained in the shielding device; wherein the nozzle system isconfigured to meet selected dispense objectives.

Also provided is a nozzle system coupled to a semiconductor fabricationsystem, the nozzle system comprising: a dispense chemical supply line; anozzle coupled to the dispense chemical supply line, the nozzlecomprising a nozzle body and nozzle tip, nozzle tip coupled to thenozzle body and configured to dispense the dispense chemical onto thesubstrate; a nozzle valve coupled to the nozzle body and the dispensechemical supply line, the nozzle valve having an opening and closingrate; and a shroud coupled to the nozzle tip and configured to create amini-environment for the dispense chemical such that a partial pressureof the dispense chemical is maintained in the nozzle shroud, the shroudhaving a shroud volume, shroud wall thickness, and shroud inner walldiameter; wherein the nozzle system is configured to meet selecteddispense objectives.

Furthermore, provided is a method of controlling a dispense nozzle witha shroud in processing a structure on a substrate, the methodcomprising: providing a nozzle system coupled to a fabrication system,the nozzle system comprising a nozzle body, a nozzle valve, a nozzletip, and a shielding device; providing a substrate to be processedinside the processing chamber of the fabrication system; startingdispense of the dispense chemical by opening the nozzle valve to flowthe dispense chemical onto a substrate in a processing chamber of thefabrication system; stopping dispense of the dispense chemical byclosing the nozzle valve to stop the flow of the dispense chemical;controlling, using a controller, the dispensing of the dispense chemicalin order to achieve one or more dispense objectives.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will become readily apparent with reference to thefollowing detailed description, particularly when considered inconjunction with the accompanying drawings, in which:

FIG. 1 is an exemplary schematic of a nozzle system with a shieldingdevice that creates an advantageous mini-environment around the nozzlein order to achieve dispense objectives;

FIG. 2 is an exemplary schematic of the nozzle system with a shroudwhere there is zero flow of the dispense chemical in an embodiment ofthe present invention;

FIG. 3 is an exemplary schematic of the nozzle system with a shroudwhere the dispense chemical is being dispensed onto a substrate in anembodiment of the present invention;

FIG. 4 is an exemplary schematic of the nozzle system with a shroudwhere the dispense of the dispense chemical has been stopped in anembodiment of the present invention;

FIG. 5 is an exemplary schematic of the nozzle system with a shroud ispositioned above a tray of the dispense chemical in an embodiment of thepresent invention;

FIG. 6 is an exemplary schematic of the shroud highlighting the keydimensions;

FIG. 7 is an exemplary schematic of a nozzle system with a shield gas inan embodiment of the present invention;

FIG. 8 is an exemplary schematic of the nozzle system using a shield gaswhere there is a plurality of nozzles in an embodiment of the presentinvention;

FIG. 9 is an exemplary flowchart of operations of a nozzle system with ashroud in an embodiment of the present invention;

FIG. 10 is an exemplary flowchart of operations of a nozzle system usinga shielding device in an embodiment of the present invention; and

FIG. 11 is an exemplary flowchart of a fabrication system with a nozzlesystem using a shielding device in an embodiment of the presentinvention.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS

In the following description, for purposes of explanation and notlimitation, specific details are set forth, such as a particulargeometry of a processing system, descriptions of various components andprocesses used therein. However, it should be understood that theinvention may be practiced in other embodiments that depart from thesespecific details.

Similarly, for purposes of explanation, specific numbers, materials, andconfigurations are set forth in order to provide a thoroughunderstanding of the invention. Nevertheless, the invention may bepracticed without specific details. Furthermore, it is understood thatthe various embodiments shown in the figures are illustrativerepresentations and are not necessarily drawn to scale.

Various operations will be described as multiple discrete operations inturn, in a manner that is most helpful in understanding the invention.However, the order of description should not be construed as to implythat these operations are necessarily order dependent. In particular,these operations need not be performed in the order of presentation.Operations described may be performed in a different order than thedescribed embodiment. Various additional operations may be performedand/or described operations may be omitted in additional embodiments.

“Substrate” as used herein generically refers to the object beingprocessed in accordance with the invention. The substrate may includeany material portion or structure of a device, particularly asemiconductor or other electronics device, and may, for example, be abase substrate structure, such as a semiconductor wafer or a layer on oroverlying a base substrate structure such as a thin film. Thus,substrate is not intended to be limited to any particular basestructure, underlying layer or overlying layer, patterned orun-patterned, but rather, is contemplated to include any such layer orbase structure, and any combination of layers and/or base structures.The description below may reference particular types of substrates, butthis is for illustrative purposes only and not limitation. For thisapplication, the words substrate and workpiece are used interchangeably.

A more complete appreciation of the invention and many of the attendantadvantages thereof will become readily apparent with reference to thefollowing detailed description, particularly when considered inconjunction with the accompanying drawings.

Chemicals used in semiconductor processes must be kept clean andparticle free in order to limit the number and size of defects createdon wafers during process. One source of particle generation on liquiddelivery systems is the dispense nozzle. Particles at the nozzle tip canbe generated in two ways. The first is by evaporation of the dispensechemical at the tip of the nozzle, which may crystalize as the materialis being delivered. The second is by chemical reaction between thedispense chemical and the surrounding air, to which it is now exposed.When the dispense chemical is not being dispensed, the dispense chemicalmay be exposed to the air for extended periods of time. Suck back valvesmay slow evaporation by maintaining a higher vapor pressure at thedispense chemical surface via the creation of a small mini-environmentat the dispense chemical surface, limiting the evaporation rate to thediffusion rate of the dispense chemical. Evaporation is not eliminatedcompletely, however. In addition, no protection from airborne molecules,such as oxygen or water, which may react with the dispense chemical, isprovided. The addition of a shroud, use of a shield gas, or acombination of both as described in this disclosure, address theseconcerns.

FIG. 1 is an exemplary schematic 100 of a nozzle system 108 with ashielding device 124 that creates an advantageous mini-environment 128around the nozzle tip 130 in order to achieve dispense objectives. Thenozzle system 108 comprises a nozzle 114, a dispense chemical 134, and ashielding device 124. The nozzle 114 includes a dispense delivery pipe104, a nozzle body 120, a nozzle valve 136, and a nozzle tip 130. If theshielding device 124 is a shroud, the mini-environment 128 is disposedinside the area surrounded by the shroud. Other configurations ofshielding devices can include shield gas or a combination of a shroudand a shield gas or the like. As will be discussed below, thesevariations and others are included in this invention.

Still referring to FIG.1, the nozzle valve 136 must be maintained inoperational condition so that flow of the dispense chemical 134 can becontrolled in a precise manner. The ideal function for the rate ofclosure of the nozzle valve 136 varies based on fluid properties,especially viscosity. In the closing operation for the nozzle system108, the dispense chemical 134 at the nozzle tip 130 should be as flatas possible, i.e., not bulging out in order to minimize the surface areaexposed. This will be covered in detail below.

FIG. 2 is an exemplary schematic 200 of the nozzle system 204 with ashroud 210 where there is zero flow of the dispense chemical 280 in anembodiment of the present invention. The nozzle 254 includes a nozzlebody 206, a dispense chemical delivery pipe 202 delivering the dispensechemical 280. The nozzle 254 also includes a nozzle tip 208 and a nozzleoutlet 212. The shroud 210 may be made of the same material as thenozzle 254 or some other material that is appropriate for the dispensechemical 280 being handled. Other dimensions of the shroud 210 include ashroud height 250, a width 216, a shroud volume 228 containing thechemical vapor 230, and a thickness of the shroud wall 220. The dispensechemical 280 is positioned inside the dispense chemical delivery pipe202 and goes all the way to the nozzle tip 208. The dispense chemical280 is kept from going into the shroud volume 228 by surface tension ofthe dispense chemical 280. The shroud volume 228 has a stable partialpressure of the dispense chemical 280 in the shroud volume 228.Effectively, a mini-environment inside the shroud volume 228 is createdaround the nozzle tip 208, similar to the environment created in thenozzle after a suck back of the dispense chemical 280 in prior artmethod of using a suck back step. In the present invention, the partialpressure of the dispense chemical 280 in the shroud volume 228 isgenerated as the dispense chemical 280 passes through the shroud area.In addition, the shroud 210 prevents external air movements from rapidlypurging the evaporated dispense chemical 280, thereby providing the sameprotection as the suck back procedure without the added complexity ofthe suck back mechanism.

FIG. 3 is an exemplary schematic 300 of the nozzle system 204 with ashroud 210 where the nozzle system 204 is flowing the dispense chemical280 onto the substrate 304 in an embodiment of the present invention.The dispense chemical 280 flows into the dispense chemical delivery pipe202, through a nozzle internal opening 308 and through the center of theshroud 210 without touching the inside wall of the shroud 224. Duringthis time, some of the dispense chemical 280 evaporates inside theshroud volume 228 and the partial pressure of the dispense chemical 280in the shroud volume 228 rises. The partial pressure of the dispensechemical 280 in the shroud volume 228 can be monitored with metrologyequipment (not shown) and such measurements can be transmitted to acontroller (not shown) that can use that data to adjust the partialpressure in the preferred range.

FIG. 4 is an exemplary schematic 400 of the nozzle system 404 with ashroud 420 where the flow of the dispense chemical 432 has been stoppedin an embodiment of the present invention. The evaporated dispensechemical 416 fills the shroud volume 428 and helps to preventevaporation at the surface 412 of dispense chemical 432. As the nozzlesystem 404 is moved, air would blow across the opening of the shroud 420and increase diffusion out of the shroud 420. Some evaporation of thedispense chemical 432 may occur as the vapor pressure of the dispensechemical is maintained within the shroud volume 428. Even with themovement of nozzle system 404, the dispense chemical 432 continues toshow a high vapor pressure at the surface 412. Without the shroud 420,the air would blow across the surface 412 of the dispense chemical 432and dramatically reduce the vapor pressure at the dispense chemical 432surface 412 and cause a correspondingly high evaporation rate. Insummary, the shroud 420 minimizes the evaporation rate from the surface412 of the dispense chemical 432 and minimize the diffusion rate of thedispense chemical vapor 416 out of the shroud 420.

FIG. 5 is an exemplary schematic 500 of the nozzle system 504 with ashroud 528 disposed in a tray 524 containing a tray chemical 520 in anembodiment of the present invention. To further aid in the minimizingthe undesired evaporation at the surface 510 of the dispense chemical530, the nozzle 506 is placed in close proximity above the tray 524containing the tray chemical 520. The tray chemical can comprise thedispense chemical or the dispense chemical and a solvent. The topportion of the tray 524 is not filled with the tray chemical 520 leavingthe unfilled portion with vapors 516. There is no contact between thenozzle shroud 528 and the tray chemical 520 in the tray 524, thus, thereis no transfer of particles (not shown) from the tray chemical 520 inthe tray 524 to the nozzle shroud 528 and the nozzle tip 508. There isalso no contact between the nozzle shroud 528 and the tray chemical 520in the tray 524. Positioning the nozzle system 504 above the tray 524allows the partial pressure of the dispense chemical 530 in the shroudvolume 512 to be maintained for an extended period of time.

FIG. 6 is an exemplary three-dimensional schematic 600 of the shroud 628highlighting key dimensions of the shroud 628 relative to the nozzlesystem 614. The critical dimensions include the diameter 608 of thenozzle inside the opening 634, distance 612 from outside the nozzle tothe inner wall of the nozzle 602, the height 628 of the shroud 638, theshroud wall thickness 620, and the inner wall diameter 632 of the shroud638.

FIG. 7 is an exemplary schematic 700 of the nozzle system 702 with ashielded zone 720 in an embodiment of the present invention. The nozzlesystem 702 comprises a nozzle 708, a dispense chemical delivery pipe716, shielding gas delivery pipe 714, shielded zone 720, and a reactivegas area 728.

The gas flow 718 is a gas mixture which is both nonreactive to thedispense chemical 704 being dispensed and also saturated with the vaporof the dispense chemical 704 that is directed as a gas flow 718proximate to the nozzle tip 724. Since the shielded zone 720 is alreadysaturated with the vapor of the dispense chemical 704, evaporation fromthe nozzle tip 724 area is prevented. The gas flow 718 is provided withsufficient energy so that it pushes away airborne reactants in thereactive gas area 728 faster than these can diffuse to the surface ofthe dispense chemical 722, then chemical reaction with the environmentis also prevented.

The embodiment includes: a) supplying a gas flow 718 where the gas flow718 comprises one or more gases, b) directing the gas flow 718 proximateto the nozzle tip 724, c) preventing evaporation from around the nozzletip 724 since the gas flow is already saturated with the vapor of thedispense chemical 704. For net evaporation to occur, the gas immediatelyabove or below the surface of the dispense chemical 704 must be belowthe saturation point of the dispense chemical 704 vapor. Net evaporationoccurs rapidly until saturation at the surface 722 of the dispensechemical 704 occurs. The high concentration of the dispense chemical 704vapor at the surface 722 of the dispense chemical 704 then diffuses intothe surrounding gas. Evaporation continues in order to replace themolecules that have diffused away. Diffusion is driven by concentrationgradient of the dispense chemical 704 in the area close to the nozzletip 724. By supplying a saturated gas flow 718 to the volume around thenozzle tip 724, the concentration gradient tends towards zero anddiffusion to the environment from the surface 722 of the dispensechemical 704 is blocked. With diffusion eliminated, evaporation of thedispense chemical 704 is also terminated.

As mentioned above, the gas flow 718 can be provided with sufficientenergy that pushes away airborne reactive gases faster than these candiffuse to the surface 722 of the dispense chemical 704, then chemicalreaction with the airborne gases in the reactive gas area 728 is alsoprevented. Diffusion occurs as Brownian motion and at typicalatmospheric pressures; the large number of molecular collisions limitsthe progression of diffusing gases. If viscous gas flow 718 is suppliedagainst the diffusing reactive gases 728 at a velocity higher than thespeed of diffusion, the progression of the diffusing reactive gases fromthe reactive gas area 728 is halted.

In some cases, the dispense chemical 704 is a compound of substanceswhich may include a volatile solvent combined with heavier, lessvolatile chemicals. In such cases, the solvent is at a much higher riskof evaporation, leaving behind the less volatile components to coagulateor crystalize. In order to avert this action, the gas flow 718 need onlycontain a saturated level of the solvent, which typically provides for asignificantly lower cost option.

The shield gas delivery pipe 714 can be supplied by a shield gasgenerator 740 which can be a bubbler where the inert gas supply (notshown) is plumbed to the bottom of the shield gas generator 740 filledwith a solvent or the dispense chemical 704, from which it bubbles up toa shield gas delivery pipe 714 that is provided as an annular gas flow718 around the nozzle 708 and released proximate to the nozzle tip 724.The shield gas generator 740 can also be a vaporizer or a similardevice. A carrier gas may also be added to the shield gas or included inthe shield gas as long as such a carrier gas is nonreactive with thedispense chemical 704. Noble gases such as argon can be used, ornitrogen gas, N2, if shown to be a compatible lower cost option, may beused as carrier gases.

The shield gas may be supplied to each nozzle individually as shown inFIG. 7 or supplied in a plenum arrangement if multiple nozzles share thesame shield gas setup as in FIG. 8 described below. The shield gasconcept can be used in conjunction with a standard nozzle, a nozzle witha suck back valve behind it, or with a nozzle that incorporates ashroud.

FIG. 8 is an exemplary schematic 800 of the nozzle system, 802 and 852,with a shield gas where there is a plurality of nozzles, 804 and 854, ina nozzle bank or plenum 894 in an embodiment of the present invention.In the embodiment, the shield gas generator (not shown) generates theshield gas 890 and is used in the nozzle bank 894 to supply a shield gasflow, 870 and 866, 820 and 816, proximate to the respective surfaces,862 and 812, of the nozzles, 804 and 854. The shield gas flow, 870 and866, 820 and 816, is supplied against the diffusing reactive gases, 828and 878, at a velocity higher than the speed of diffusion, causing theprogression of the diffusing reactive gases, 828 and 878, to stop. Asmentioned above, by supplying a saturated gas supply to the surfaces, ofthe dispense chemical in the respective nozzles, 804 and 854, theconcentration gradient tends towards zero and diffusion to theenvironment from the surfaces, 812 and 862, of the dispense chemicals,808 and 858, are blocked. With diffusion eliminated, the shielded zones,874 and 824, are already saturated with the vapor of the dispensechemicals, 808 and 858, evaporation from the respective surfaces, 812and 862, is prevented.

FIG. 9 is an exemplary flowchart 900 of operations of a nozzle systemwith a shroud in an embodiment of the present invention. In operation904, a nozzle system coupled to a process chamber in a fabricationsystem is provided, the nozzle system comprising a nozzle body, nozzlevalve, a nozzle tip, and a shroud. The shroud can be an extension of thenozzle body or it can be a different annular material attached to thenozzle body. The fabrication system can be an etch, cleaning, rinsing,or liquid treatment system. In operation 908, a workpiece is provided inthe process chamber, the workpiece requiring use of the nozzle system todispense a chemical onto the workpiece. The workpiece can be a wafer,substrate, memory device, flat panel display device, or the like. Forsimplicity, all later references to the workpiece will instead state asubstrate.

In operation 912, the nozzle system is started by performing a sequenceof opening operations. The sequence of opening operations may includemoving an arm containing the one or more nozzle systems from a standbyposition to a specific position above the substrate. Another openingoperation may include moving the nozzle from a tray partially filledwith the tray chemical or dispense chemical and a solvent to thespecific position above the substrate. If this is the first time thenozzle system is being used, an opening sequence of operations mayinclude flowing the dispense chemical to the inner opening of the nozzlein order to start increasing the partial pressure of the dispensechemical in the shroud or mini-environment space below the nozzle inneropening. In operation 916, the dispense chemical is dispensed onto thesubstrate, the dispense having a dispense flow rate, a dispense chemicalpartial pressure at the nozzle tip, and a dispense temperature. Duringthis operation, static electrical energy may build up in the nozzlesystem during the dispense operation. Static electrical energy issuescan be eliminated by providing a conductive grounded surface on theinside wall of the shroud.

Still referring to FIG. 9, in operation 920, the nozzle system isstopped by performing a sequence of closing operations. The sequence ofclosing operations may include moving the arm containing the one or morenozzle systems from a specific position above the substrate to a standbyposition. Another closing operation may include moving the nozzle fromspecific position above the substrate to a tray partially filled withthe tray chemical. Still another closing operation may include rinsingthe nozzle system in preparation for another, different dispensechemical. In operation 924, sequence of operations including thestarting of the nozzle system, dispensing the dispense chemical, andstopping of the nozzle system is performed a prescribed number of timesdepending on the application. In operation 928, selected one or moreoperating variables of the nozzle system are concurrently controlled inorder to achieve objectives of the dispense nozzle application. Theobjectives of the dispense nozzle application can include no dripping ofdispense chemical when dispense has stopped, no particle contaminationof substrate, and/or lower cost of ownership.

FIG. 10 is an exemplary flowchart 1000 of operations of a nozzle systemwith a shielding device in an embodiment of the present invention. Inoperation 1004, a nozzle system coupled to a process chamber in afabrication system is provided, the nozzle system comprising a nozzlebody, nozzle valve, a nozzle tip, and a shielding device. The shieldingdevice can be a shield gas such as the shield gas described in relationto FIG. 7 and FIG. 8. Alternatively, the shielding device may also use anozzle with a shroud. Other variations of the shroud and the shield gasmay also be used. As stated above, the fabrication system can be anetch, cleaning, rinsing, or liquid treatment system. In operation 1008,a substrate is provided in the process chamber, the substrate requiringuse of the nozzle system to dispense a chemical onto the substrate.

In operation 1012, the nozzle system is started by performing a sequenceof opening operations. The sequence of opening operations may includemoving an arm containing the one or more nozzle systems from a standbyposition to a specific position above the substrate. Another openingoperation may include moving the nozzle from a tray partially filledwith the dispense chemical or the dispense chemical with a solvent tothe specific position above the substrate. If this is the first time thenozzle system is being used, an opening sequence of operations mayinclude flowing the dispense chemical through the dispense chemicaldelivery pipe to the inner opening of the nozzle in order to startincreasing the partial pressure of the dispense chemical in thegas-shielded space, shrouded space or mini-environment space below thenozzle inner opening. In operation 1016, the dispense chemical isdispensed onto the substrate, the dispense having a dispense flow rate,a dispense chemical partial pressure at the nozzle tip, and a dispensetemperature.

Still referring to FIG. 10, in operation 1020, the nozzle system isstopped by performing a sequence of closing operations. The sequence ofclosing operations may include moving the arm containing the one or morenozzle systems from a specific position above the substrate to a standbyposition. Another closing operation may include moving the nozzle fromspecific position above the substrate to a tray partially filled withthe tray chemical. Still another closing operation may include rinsingthe nozzle system in preparation for another different dispensechemical. In operation 1024, sequence of operations including thestarting of the nozzle system, dispensing the dispense chemical, andstopping the nozzle system is performed a prescribed number of timesdepending on the application. In operation 1028, selected one or moreoperating variables of the nozzle system are concurrently controlled inorder to achieve objectives of the dispense nozzle application. Asmentioned above, the objectives of the dispense nozzle application caninclude no dripping of dispense chemical when dispense has stopped, noparticle contamination of substrate, and/or lower cost of ownership.

The delivery of the dispense chemical to the inner opening of the nozzleshould be tuned to minimize the surface area of the exposed dispensechemical and to ensure that the surface area is as flat as possible,i.e., not bulging out. By ensuring flatness of the surface area, amini-environment is created around the nozzle tip similar to theenvironment created in the nozzle tip using a suck back process.However, in this case, the partial pressure of evaporated dispensechemical is generated by the flow of the dispense chemical passingthrough the zone including the nozzle tip and does not use a suck backthat is typically performed with complex, expensive equipment.

FIG. 11 is an exemplary schematic 1100 of a fabrication system with anozzle system using a shroud or shielding device in an embodiment of thepresent invention. The nozzle system 1104 is coupled to a controller1155 and to a fabrication system 1108. The controller 1155 can comprisea microprocessor, memory, and a digital I/O port capable of generatingcontrol voltages sufficient to communicate and activate inputs to thenozzle system 1104 and to the processing system 1108 as well as monitoroutputs from processing system 1108. Moreover, controller 1155 can becoupled to and can exchange information with nozzle system 1104 andsubsystems of the fabrication system 1108. For example, a program storedin the memory can be utilized to activate the inputs to theaforementioned subsystems of fabrication system 1108 and of the nozzlesystem 1104 according to a process recipe in order to perform a dispenseprocess on a substrate.

Depending on the applications, additional devices such as sensors ormetrology devices can be coupled to the nozzle system 1104 and to thefabrication system 1108 and the controller 1155 can collect real timedata and use such real time data to concurrently control one or moreselected operating variables in two or more steps involving dispensechemical flow rate, dispense chemical temperature, dispense chemicalviscosity, presence of contaminants, partial pressure of the dispensechemical around the nozzle tip, and the like in order to achievedispense objectives.

Specifically, the controller 1155 coupled to the nozzle system 1104 canbe configured to perform sequences of operations based on instructionsstored in a storage device, memory, or based on data communicated by thesensor or by external computer networks. One or more sensors can beprogrammed to detect the presence of contaminants or dripping of thedispense chemical after a dispense and in conjunction with thecontroller resolve the problem. The fabrication system 1108 can be anetch, cleaning, rinsing, tract, or fluid treatment semiconductorfabrication system. Further, the controller can be configured to utilizeselected operating variables which are concurrently controlled toachieve the dispense objectives, the dispense objectives comprising costof ownership, throughput samples per hour, reduced particlecontamination, and reduced usage of the dispense chemical.

Although only certain embodiments of this invention have been describedin detail above, those skilled in the art will readily appreciate thatmany modifications are possible in the embodiments without materiallydeparting from the novel teachings and advantages of this invention. Forexample, the applications of the principles and techniques of fluidmixing using a spiral mixer where a selected two or more mixingvariables are concurrently controlled to meet target objectives havemany other uses in addition to semiconductor manufacturing. Accordingly,all such modifications are intended to be included within the scope ofthis invention.

What is claimed is:
 1. A nozzle system coupled to a semiconductorfabrication system, the nozzle system comprising: a dispense chemicalsupply line; a nozzle coupled to the dispense chemical supply line, thenozzle comprising a nozzle body and nozzle tip, the nozzle tip coupledto the nozzle body and configured to dispense the dispense chemical ontothe substrate; a nozzle valve coupled to the nozzle body and thedispense chemical supply line, the nozzle valve having an opening andclosing rate; and a shroud coupled to the nozzle tip and configured tocreate a mini-environment for the dispense chemical such that a partialpressure of the dispense chemical is maintained in the nozzle shroud,the shroud having a shroud volume, shroud wall thickness, and shroudinner wall diameter, the nozzle tip having a dispense area; wherein thenozzle system is configured to meet selected dispense objectives.
 2. Thenozzle system of claim 1 wherein the selected dispense objectivesinclude the nozzle valve meeting a nozzle valve opening and closing ratethat enables the nozzle tip to avoid dripping of the dispense chemicalafter completion of a dispense operation, no particle contamination ofthe substrate, and/or lower cost of ownership.
 3. The nozzle system ofclaim 1 wherein the selected dispense objectives include controlling thedispense chemical partial pressure in the shroud volume to an acceptablerange.
 4. The nozzle system of claim 1 wherein the dispense chemicalincludes a resist, a solvent, or one or more semiconductor chemicals. 5.The nozzle system of claim 1 further comprising a tray partially filledwith a tray chemical wherein the nozzle with the shroud is placedimmediately above the tray chemical when the nozzle system is not inuse.
 6. The nozzle system of claim 1 wherein if the nozzle is notdispensing the dispense chemical, the dispense area of the nozzle tip isminimized in order to keep the dispense chemical at the nozzle tip asflat as possible.
 7. The nozzle system of claim 1 wherein the dispensechemical is held in place in the dispense area by surface tension in thedispense chemical.
 8. The nozzle system of claim 1 wherein partialpressure of the dispense chemical is a function of the shroud wallthickness and shroud inner wall diameter.
 9. The nozzle system of claim1 wherein partial pressure of the dispense chemical is controlled in theshroud by disposing the nozzle in a tray containing a tray chemicalclose to but not touching the tray chemical.
 10. The nozzle system ofclaim 9 wherein disposing the nozzle in the tray minimizes a rate ofevaporation of the dispense chemical into the shroud and minimizes adiffusion of the dispense chemical out of the shroud.
 11. The nozzlesystem of claim 1 wherein the rate of nozzle valve opening and closingare a function of the viscosity and flow characteristics of the dispensechemical; or wherein when the dispense chemical is flowing, the dispensechemical flows out of the internal opening of the nozzle and wherein thedispense chemical does not touch the wall of the shroud.
 12. The nozzlesystem of claim 1 further comprising a controller configured to controldispense operating variables including flow rate of the dispensechemical, partial pressure of the dispense chemical inside the shroudvolume, and temperature of the shroud volume in order to meet thedispense objectives.
 13. A nozzle system for dispensing a dispensechemical onto a substrate, the system comprising: a nozzle comprising anozzle body and a nozzle tip; a shielding device coupled to the nozzletip, the shielding device configured to create a mini-environment for adispense chemical such that a partial pressure of the dispense chemicalis maintained in the shielding device; wherein the nozzle system isconfigured to meet selected dispense objectives.
 14. The nozzle systemof claim 13 wherein the shielding device is a nozzle shroud.
 15. Thenozzle system of claim 13 wherein the shielding device is a gas shield.16. The nozzle system of claim 13 wherein the shielding device is anozzle shroud and/or a gas shield.
 17. The nozzle system of claim 15wherein the nozzle system further comprises a gas shield generatorcoupled to the nozzle system and configured to generate the gas shieldcomprising a shield gas flow to a shielded zone proximate the nozzletip.
 18. The nozzle system of claim 15 wherein the nozzle comprises aplurality of nozzles in a nozzle bank.
 19. The nozzle system of claim 18wherein the gas flow to the shielded zone is at a velocity higher than aspeed of diffusion of reactive gases, the gas flow causing terminationof dispense chemical evaporation.
 20. The nozzle system of claim 15further comprising a controller configured to utilize selected operatingvariables which are concurrently controlled to achieve dispenseobjectives, the dispense objectives comprising cost of ownership,throughput substrates per hour, reduced particle contamination, andreduced usage of the dispense chemical.
 21. A method of controlling adispense nozzle with a shroud in processing a substrate, the methodcomprising: providing a nozzle system coupled to a fabrication system,the nozzle system comprising a nozzle body, a nozzle valve, a nozzletip, and a nozzle shroud; providing a substrate to be processed insidethe processing chamber of the fabrication system; starting dispense ofthe dispense chemical by opening the nozzle valve to flow the dispensechemical onto a substrate in a processing chamber of the fabricationsystem; stopping dispense of the dispense chemical by closing the nozzlevalve to stop the flow of the dispense chemical; controlling, using acontroller, the starting dispense and stopping dispense of the dispensechemical in order to achieve one or more dispense objectives.
 22. Themethod of claim 21 wherein the one or more nozzle dispensing objectivesinclude no dripping of the dispense chemical after the nozzle valve isclosed and wherein partial pressure of the dispense chemical in thenozzle shroud area is kept within a range by controlling amini-environment of the nozzle shroud.
 23. The method of claim 21wherein one or more nozzle dispense objectives includes the opening andclosing rate of the nozzle valve is controlled to be able to handle theviscosity and other fluid characteristics of the dispense chemical. 24.A method of controlling a dispense nozzle with a shielding device inprocessing a structure on a substrate, the method comprising: providinga nozzle system coupled to a fabrication system, the nozzle systemcomprising a nozzle body, a nozzle valve, a nozzle tip, and a shieldingdevice; providing a substrate to be processed inside a processingchamber of the fabrication system; starting dispense of a dispensechemical by opening the nozzle valve to flow the dispense chemical ontoa substrate in the processing chamber of the fabrication system;stopping dispense of the dispense chemical by closing the nozzle valveto stop the flow of the dispense chemical; controlling, using acontroller, dispensing of the dispense chemical in order to achieve oneor more dispense objectives.
 25. The method of claim 24 wherein the oneor more dispense objectives include no dripping of the dispense chemicalafter the nozzle valve is closed and partial pressure of the dispensechemical in the nozzle shroud area is kept within a range by controllingthe mini-environment of the nozzle shroud.
 26. The method of claim 24wherein one or more dispensing objectives includes an opening andclosing rate of the nozzle valve is controlled to be able to handle theviscosity and other fluid characteristics of the dispense chemical. 27.The method of claim 24 wherein the shielding device is a nozzle shroud,a gas shield, or a combination of a nozzle shroud and a gas shield.